A number of devices have been proposed for sensing liquids to determine a liquid level, for example, or sense the presence or absence of liquid in a flow line. However, there is a need for a low-cost sensor, particularly in the automotive field, for sensing liquids and providing a remote indication or control. In addition to being low in cost, it is desirable that the sensor be rugged and foolproof. It must have long term stability and reliability, must operate over a wide temperature range, and be capable of operating with a variety of fluids, including flammable, corrosive, and electrically conductive liquids.